1. Field of the Invention
The present invention relates to a medical pressure-sensitive adhesive sheet and a method for producing the same. In particular, it relates to a medical pressure-sensitive adhesive sheet excellent in elasticity, handling or the like while maintaining excellent moisture permeability or water resistance and a method for producing such a medical pressure-sensitive adhesive sheet.
2. Description of the Related Art
Hitherto, various kinds of medical pressure-sensitive adhesive sheets have been proposed which exhibit excellent moisture permeability or elasticity and also favorable water proofing property or the like.
For example, a pressure-sensitive adhesive film for first-aid adhesive plaster has been proposed in which skin irritation due to the occurrence of sweatiness is prevented without inhibiting the cutaneous respiration (for example, see JP 8-33673 A (claims or the like)).
More specifically, as illustrated in FIG. 6B, it is a pressure-sensitive adhesive film for first-aid adhesive plaster 100 formed by pattern coating one surface of a nonwoven fabric 101 composed of a SIS block copolymer or the like with a porous pressure-sensitive adhesive 102. In the pressure-sensitive adhesive film for first-aid adhesive plaster 100, another substrate 106 such as a polyurethane film is thermally laminated on the surface of the nonwoven fabric 101 which is the side opposite to the surface coated with the pressure-sensitive adhesive 102, and further an edge portion 105 is sealed.
Meanwhile, as illustrated in FIG. 6A, it is a pressure-sensitive adhesive film for first-aid adhesive plaster 100 in which a pad 104 is provided at a predetermined place of the pressure-sensitive adhesive 102 and two release sheets 103 are layered so as to conceal the pressure-sensitive adhesive 102 including the pad 104.
In addition, an electron beam resistant medical covering material has been proposed which exhibits sufficient flexibility, excellent strength, and electron beam resistance as well as moisture permeability and water proofing property (for example, see JP 4,139,482 B1 (claims or the like)).
More specifically, it is an electron beam resistant medical covering material which has a three-layer structure and is formed by thermally laminating a nonwoven fabric sheet containing an ethylene • α-olefin copolymer on both sides of a substrate such as a polyether block amide copolymer film having a water bearing pressure of 2000 mm H2O or more and a moisture permeability amount of 1500 g/m2·24 hours or more.
In addition, a medical sheet consisting of a predetermined polyurethane nonwoven fabric/hot melt type adhesive/polyurethane film and a method for producing the same have been proposed for the purpose to improve elasticity, breathability, moisture permeability, water proofing property or the like (for example, see WO 2007-114295 (claims or the like)).
More specifically, it is a medical sheet formed by thermally laminating a polyurethane nonwoven fabric formed from a fiber having an average fiber diameter of 50 μm or less by the melt blow method and a polyurethane film having micropores (through holes) with a diameter of 10 μm or less formed on both sides thereof using the phase separation phenomenon via a pattern coated hot melt type adhesive.
In addition, an elastic nonwoven fabric has been proposed which is used in a medical material or the like and exhibits sufficient strength or favorable sticking property (anti-blocking property) as well as excellent elasticity and flexibility (for example, see JP 2008-7930 A (claims or the like)).
More specifically, it is an elastic nonwoven fabric formed by melt spinning a mixture (mixing weight ratio=50/50 to 95/5) of a thermoplastic elastomer component (A) such as an elastomeric polypropylene having an MFR value of 50 to 400 g/10 minutes and a polypropylene resin (B) having an MFR value of 25 to 200 g/10 minutes.
Moreover, a pasting material has been proposed which is excellent in pasting ability to the human skin and consists of a predetermined polyurethane elastomer film and a predetermined pressure-sensitive adhesive layer (for example, see JP 4,755,284 B1 (claims or the like).
More specifically, it is a pasting material which has a layer structure in which a pressure-sensitive adhesive layer is provided on one surface of the substrate layer and satisfies the following features (a) to (f).
(a) The substrate layer is a polyurethane elastomer film having a thickness within the range of from 1 to 8 μm.
(b) The thickness of the pressure-sensitive adhesive layer is within the range of from 1 to 10 μm.
(c) The total thickness of the substrate layer and the pressure-sensitive adhesive layer is within the range of from 2 to 15 μm.
(d) The 10% tensile load of the pasting material measured in conformity with JIS Z 0237 of the Japanese Industrial Standards is within the range of from 0.03 to 1.1 N/10 mm in each of the longitudinal and transverse directions.
(e) The product XY value of the 10% tensile load value X and the thickness value Y of the pasting material is within the range of from 0.1 to 12 or the product XZ value of the 10% tensile load value X and the thickness value Z of the substrate layer is within the range of from 0.05 to 6.8 when the 10% tensile load value of the pasting material in the longitudinal direction is denoted as X (N/10 mm), the thickness value of the pasting material is denoted as Y (μm), and the thickness value of the substrate layer is denoted as Z (μm).
(f) The pressure-sensitive adhesive layer exhibits an adhesive force of from 0.15 to 2 N/10 mm in the 90° peeling test of a pair of bakelite plates defined in JIS Z 0237.